Digital camera and external device for image storage and camera control

ABSTRACT

This patent discloses a digital camera and an external device for both storing digital images from the camera and controlling certain camera functions. The external device may be either directly attached to the camera or remotely attached by way of a cable or similar device. The external device may also include a means for recording images onto removable recording media. The external device may also include a button for sending instructions to the camera to allow for switching between image resolution modes, flash lighting modes, and autofocusing modes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital camera such as electronicstill camera, an external storage device for externally storing theimage data within this digital camera, and a system made of them, and,in particular, to an external storage device which can set operationalfunctions of the digital camera from the outside.

2. Related Background Art

Electronic still camera is an apparatus which captures an image of asubject by using a solid-state imaging device such as CCD. An analogsignal output from the solid-state imaging device is AD-converted and,after being subjected to a predetermined processing, stored in a mainmemory within the electronic still camera. The main memory isconstituted by a semiconductor non-volatile memory such as E²PROM.

SUMMARY OF THE INVENTION

The number of E²PROMs which can be installed within an electronic stillcamera, however, is restricted by the size of the housing of the camera.Accordingly, in order to record or keep a larger number of images,external storage devices which are to be connected to the electronicstill camera by way of a cable have been developed. While theconventional external storage device has only a function of recordingand reproducing image data, functional setting of the camera is effectedon the camera side. In an electronic still camera using an LCD,information about functional settings of the camera is displayed on theLCD, so as to provide users with necessary information. Nevertheless, asvarious kinds of information are displayed on the same LCD attached tothe electronic still camera, it is difficult for users who are notaccustomed to electronic instruments to discern such information.

The present invention relates to a digital camera such as electronicstill camera, an external storage device connected to this digitalcamera by way of a cable or the like, and a system made of them.

The digital camera in accordance with the present invention comprises asolid-state imaging device which captures an image of a subject; a firststorage device which stores, selectively with a first or secondresolution, image data of the subject output from the solid-stateimaging device; a second storage device which stores a program includingan instruction for switching, according to an order from outside of thedigital camera, the resolution of the image data stored in the firststorage device; a first control section which executes the programstored in the second storage device; and a terminal to which the orderfrom the outside is input.

An external storage device connected to the terminal of this digitalcamera comprises a housing; a liquid crystal display attached to oneside face of the housing; and a second control section which orders, byway of the terminal, the digital camera to rewrite the instruction andcauses the liquid crystal display to show information about theresolution of the digital camera.

Further, in a system constituted by a digital camera and an externalstorage device, the digital camera comprises a first housing; asolid-state imaging device which is disposed within the first housingand captures an image of a subject; a first storage device which isdisposed within the first housing and temporarily stores image data ofthe subject; a second storage device which is disposed within the firsthousing; and a first control section which is disposed within the firsthousing, reads out the image data stored in the first storage device,and converts the image data according a predetermined instruction so asto write thus converted data into the second storage device. Also, thisexternal storage device comprises a second housing having an openinginto which a recording medium to store the image data is inserted; aterminal attached to the second housing; and a second control sectionwhich is disposed within the second housing, reads out, by way of theterminal, the image data stored in the second storage device of thedigital camera, writes thus read-out data into the recording medium, andtransmits a control signal for changing the predetermined instruction tothe first control section of the digital camera by way of the terminal.

The present invention will be more fully understood from the detaileddescription given hereinbelow and the accompanying drawings, which aregiven by way of illustration only and are not to be considered aslimiting the present invention.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will beapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an external storage device;

FIG. 2 is an explanatory view of a camera system constituted by anexternal storage device and a digital camera;

FIG. 3 is a block diagram showing a configuration of a camera system;

FIG. 4 is an explanatory view for explaining an indicator on a liquidcrystal display;

FIG. 5 is an explanatory view for explaining an indicator on the liquidcrystal display;

FIG. 6 is an explanatory view for explaining an indicator on the liquidcrystal display;

FIG. 7 is an explanatory view for explaining an indicator on the liquidcrystal display; and

FIGS. 8 to 10 are flow charts for explaining operations of an externalstorage device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will beexplained. In the following explanation, constituents identical to eachother will be referred to with marks identical to each other, withouttheir overlapping explanations repeated.

FIG. 1 is a plan view of an external storage device OM. An end portionof a housing 1 forms a battery box 2. When a battery is placed withinthis battery box 2, and a power switch button 3 is then pushed down, theexternal storage device OM is actuated, thereby lighting a liquidcrystal display (LCD) 4 attached to the same face of the housing 1 onwhich the button 3 is located. The LCD 4 shows the numbers ofphotographed shots within a camera and within a memory card (recordingmedium) 5, whether or not the recording medium is attached, the batteryvoltage, and the like. FIG. 1 shows a state where the LCD 4 is totallylighted. In the following explanation, the face of the housing 1 onwhich the LCD 4 is disposed will be referred to as upper face.

At the front face of the housing 1, disposed is an opening 5 a throughwhich the memory card 5 is inserted into the front face of the housing 1in parallel thereto. When pushed into the housing 1 by way of thisopening 5 a, the memory card 5 is stabilized with respect to the housing1. At the front face of the housing 1, disposed is an eject button 6which is protruded in a direction in parallel to the upper face of thehousing 1. When the eject button 6 is urged toward the inside of thehousing 1, the locking mechanism of the memory card 5 which has beeninserted into the housing 1 is released, so that the memory card 5 canbe taken out from the inside of the housing 1.

As will be explained later, the memory card 5 stores image data within adigital camera to which the external storage device OM is connected. Theexternal storage device OM is connected to the digital camera by way ofa terminal 7. When a copy switch button 8 is pushed down, the image datawithin the digital camera can be transferred into the memory card 5.Also, when an erase switch button 9 is pushed down, the image datastored within the memory card 5 are erased.

FIG. 2 shows a camera system constituted by a digital camera CA and theexternal storage device OM. The terminal 7 of the external storagedevice OM is connected to the digital camera CA by way of a cable 10.Here, the digital camera CA and the external storage device OM areconnected to each other through a serial interface. The digital cameraCA comprises a finder 11, a photographing lens 12, and a shutter releasebutton 13 which are attached to a housing 25, as well as a storagedevice therewithin which stores image data of a subject which has formedan image incident on the inside of the digital camera CA by way of thephotographing lens 12.

FIG. 3 is a block diagram showing a camera system constituted by thedigital camera CA and the external storage device OM.

The digital camera CA is controlled by a control unit 14 constituted bya main board. Namely, the control unit 14 is a microcomputer unitcomprising a central processing unit (CPU) 15, which is a controlsection for executing an operation, and a read-only memory (ROM) 16which stores a program used at the time when the CPU is actuated and thelike. Namely, the control section 15 executes the program written intothe ROM 16. The unit is actuated when a switch SW is turned on so as tosupply an electric power from a power circuit 24 to the main board 14.

Light reflected by a subject S is transmitted through the photographinglens 12 so that it can be made incident on a single-plate color CCDimage sensor 17. Namely, the subject S forms an image on alight-receiving surface of the image sensor 17. Here, the image sensor17 includes a CCD (solid-state imaging device), which comprises aplurality of pixels arranged two-dimensionally, and a circuit forapplying a transfer clock to each pixel. As the CCD, that used for VTRis employed.

A CCD output signal from the image sensor 17 is converted into a videosignal by a front-end circuit 18 including an amplifier circuit and asample holding circuit, and thus obtained video signal is converted intoa quantized digital signal by an AD converter 19.

The video signal is directly AD-converted by the AD converter 19 andstored in a frame memory (storage device) 20 which can accumulate imagedata for at least one picture. The frame memory 20 is controlled by thecontrol unit 14. The frame memory 20 is a so-called PSRAM. whichapparently functions as static random access memory (SRAM). A mainmemory 21 is also disposed within the housing 25. The main memory 21 isa non-volatile memory which enables both readout and writing and, morespecifically, is an electrically erasable programmable ROM (E²PROM)which can erase the voltage at its floating gate when a voltage isapplied to its control gate.

The image data temporarily stored in the frame memory 20 are writteninto the main memory (storage device) 21 according to an order from thecontrol section 15. Namely, according to the instruction stored withinthe ROM 16, the control section 15 reads out the image data stored inthe frame memory 20, converts thus read-out image data, and writes thusconverted data into the main memory 21. This writing operation has twomodes. One of them is a high-resolution mode in which high-resolutionimage data temporarily stored in the frame memory 20 are read out andall of thus read-out data are written into the main memory 21. The otheris a low-resolution mode in which the high-resolution image datatemporarily stored in the frame memory 20 are read out and then thusread-out image data are written into the main memory 21, while a partthereof is skipped, such that the amount of data becomes ½ of thehigh-resolution image data. Namely, under the low-resolution mode, imagedata twice as large as those of the high-resolution image data can bestored in the same capacity (available space) of memory. These modes canbe switched therebetween as the instruction within the ROM 16 isrewritten according to an order from the external storage device OM.Namely, the program stored within the ROM 16 of the digital camera CAincludes an instruction for setting the operational outline of thesystem, and this instruction further includes therewithin an instructionfor switching, according to the order from the outside of the digitalcamera, the resolutions of the image data to be stored in the mainmemory 21. Here, at the time of this writing operation, the image datastored in the frame memory may be written into the main memory as beingcompressed.

The image data stored in the main memory 21 are copied or transferred tothe recording medium 5 within the external storage device OM by way of atransmitting and receiving circuit 23 of the digital camera CA and atransmitting and receiving circuit 26 of the external storage device OM.The image data being transmitted are temporarily accumulated in acommunication buffer 22 from the main memory 21 by the control section15, and then sequentially transferred to the transmitting circuit 23,from which they are transferred to the external storage device OM by wayof terminals 29 and 7. The data being received are temporarily stored inthe communication buffer 22 by way of the receiving circuit 23 and thensequentially read out by the control section 15.

The external storage device OM is controlled by a control section 27 awhich is a CPU or the like. The instruction to be executed by thecontrol section 27 a is stored in a ROM 27 b. In FIG. 3, an operatingsection CP is assumed to include the buttons 8 and 9 in FIG. 1.

FIGS. 8 to 10 are flow charts for explaining operations of the controlsection 27 a in the external storage device OM. The control section 27 aperforms operations shown in these flow charts by executing a programincluding a plurality of instructions written in the ROM 27 b.

When the power switch button 3 is pushed down (step 1 (S1)), an electricpower is supplied from a power circuit 28 to the control section 27 aand the like, whereby the device is actuated on the basis of the programstored in the ROM 27 b of this device.

When the memory card 5 is placed within a cavity 5 b of the externalstorage device, a non-depicted sensor detects information about theexistence of the memory card 5. This sensor is connected to the controlsection 27 a, which judges whether the memory card 5 is placed withinthe cavity 5 b or not (step 2 (S2)). When it is judged that the memorycard 5 is not inserted, the control section 27 a causes the display 4 toshow information about the nonexistence of the memory card 5 as “NOCARD” (step 11 (S11)). Here, when it is judged that the memory card 5 isinserted, the control section 27 a causes the display 4 to show a cardicon 4 a depicted in FIG. 4.

The control section 27 a judges whether the external storage device OMis connected to the digital camera OM or not (step 3 (S3)).Specifically, this judgment is effected as it is judged whether theterminal 7 of the external storage device OM is connected to theterminal 29 of the digital camera CA or not. When it is judged that theexternal storage device OM is not connected to the digital camera CA,the control section 27 a causes the display 4 to show information aboutthis unconnected state as “NO CON” (step 12 (S12)).

When it is judged that the external storage device OM is connected tothe digital camera CA, the control section 27 a detects the availablespace on the memory card 5 (step 4 (S4)). Then, the control section 27 acauses the display 4 to show information about thus detected availablespace on the memory card 5 in terms of percent as depicted by anindicator 4 b of FIG. 4 (step 5 (S5)).

Further, the control section 27 a detects the number of image data fileswithin the memory card 5 (step 6 (S6)). Then, the control section 27 acauses the display 4 to show information about thus detected number ofimage data files as depicted by an indicator 4 c of FIG. 4 (step 7(S7)). Also, the control section 27 a judges the battery voltage andcauses the display 4 to show information about the battery voltage asdepicted by an icon 4 d of FIG. 4. When the battery voltage issufficient for driving the external storage device OM, regions 4 e and 4f are lighted. When the battery voltage is insufficient for continuouslydriving the external storage device OM for at least 30 minutes, theregion 4 e of the icon 4 d is not lighted while the region 4 f islighted. Also, when the battery voltage is insufficient for driving theexternal storage device OM, the icon 4 d is not lighted.

Namely, according to orders from the control section 27 a, the display 4indicates information about image data within the memory card 5,information about the battery voltage, and the like.

More specifically, in the state where no image data are stored in thedigital camera CA, when the external storage device OM and the digitalcamera CA are connected to each other by way of the cable 10 and boththeir power supplies are turned on, information depicted in FIG. 4 isshown on the LCD 4. Namely, the upper region 4 b of the LCD 4 indicatesthe capacity recordable within the memory card 5 in terms of %, whileits lower region 4 c displays the recorded image data within the memorycard 5 in terms of the number of shots. Since no image data are storedwithin the memory card 5, the upper region 4 b and lower region 4 c ofthe LCD 4 show characters of 100% and 0, respectively.

Then, the control section 27 a judges whether the all-erase button 9 ispushed down or not (step 8 (S8)). When it is judged that the all-erasebutton 9 is pushed, the control section 27 a erases the data within thememory card 5 (step 13 (S13)).

When it is judged that the all-erase button 9 is not pushed, the controlsection 27 a judges whether the copy button 8 is pushed or not (step 9(S9)).

When it is judged that the copy button 8 is not pushed, the controlsection 27 a judges whether the power button 3 is pushed or not (step 10(S10)). When it is judged that the power button 3 is pushed, the controlsection 27 a stops supplying the electric power from a non-depictedbattery (step 14 (S14)).

When it is judged that the power button 3 is not pushed, the controlsection 27 a judges whether or not 90 seconds have passed without anybutton being pushed (step 15 (S15)). When it is judged that 90 secondshave passed without any button being pushed, the control section 27 astops supplying the electric power from the non-depicted battery (step14 (S14)). When it is judged that 90 seconds have not passed without anybutton being pushed, the control section 27 a re-executes theinstruction of step 2 (S2).

In the case where the copy button 3 is pushed at step 9 (S9), thecontrol section 27 a transmits, to the digital camera CA, a commandrequesting information about whether the main memory 21 in the digitalcamera CA contains image data or not (step 100 (S100)). Thus transmittedcommand is detected at the control section 15 by way of the transmittingcircuit 23 and the communication buffer 22. The control section 15 isoperated by the program including the instruction written in the ROM 16.When the control section 15 of the digital camera CA receives theabove-mentioned command, it detects the information about whether imagedata exist within the main memory 21 or not, and transmits thus detectedinformation to the external storage device OM. Accordingly, the controlsection 27 a of the external storage device OM receives the informationabout whether image data exist within the digital camera CA or not (step101 (S101)).

From thus received information, the control section 27 a judges whetherimage data exist within the digital camera CA or not (step 102 (S102)).When it is judged that image data exist within the digital camera CA,the control section 27 a transmits, to the control section 15 of thedigital camera CA, a command requesting transmission of the image datawithin the main memory 21 (step 103 (S103)). Receiving this request fortransmitting the image data, the control section 15 of the digitalcamera CA transmits the image data within the main memory 21 to thecontrol section 27 a of the external storage device OM. Receiving theimage data (step S104 (S104)), the control section 27 a writes thusreceived image data into the memory card 5 (step 105 (S105)). In otherwords, the control section 27 a stores the memory card 5 with the imagedata transmitted to the control section 27 a from the main memory 21 ofthe digital camera CA.

Namely, in the state where image data are stored in the digital cameraCA, when the external storage device OM and the digital camera CA areconnected to each other by way of the cable 10, and the copy button 8 inthe operating section CP is then pushed down, the control section 27 aof the external storage device OM transmits a control signalcorresponding to copying, by way of the transmitting and receivingcircuits 26 and 23, to the communication buffer 22. The control section15 of the digital camera CA detects the control signal transferred tothe communication buffer 22, and the instruction for the copying mode isexecuted in response to this control signal.

The instruction for the copying mode is also stored within the ROM 16.In the copying mode, the control section 15 reads out the image datawithin the main memory 21, temporarily stores thus read-out datatogether with control codes such as header and trailer including a flagsequence added thereto, and transfers thus stored data to the externalstorage device OM by way of the transmitting and receiving circuit 23.While performing error check of thus transmitted data, the transmittingand receiving circuit 26 of the external storage device OM receives thedata. The control section 27 a reads out thus received data and writesthe read-out data into the memory card 5. Here, as mentioned above, theimage data stored within the memory card 5 can be erased when theall-erase button 9 in the operating section CP is pushed down.

In the following, an operation for changing the resolution of thedigital camera effected by the external storage device OM will beexplained. Though the following explanation relates to an example wherethe photographing mode of the digital camera is changed from a highresolution mode allowing 8 shots to be photographed to a low resolutionmode allowing 16 shots to be photographed, the reverse change can beeffected in a similar manner.

When it is judged at step 102 (S102) that no image data exist within themain memory 21, the control section 27 a transmits, to the digitalcamera CA, a command requesting information about resolution (step 200(S200)). It takes about 0.5 second for the digital camera CA to respondto this command. Accordingly, the control section 27 a causes thedisplay 4 to show an arrow mark such as that depicted in FIG. 5 for onesecond (step 201 (S201)).

Receiving the command for requesting the resolution information, thecontrol section 15 of the digital camera CA transmits the resolutioninformation (whether the resolution is high or low) to the controlsection 27 a of the external storage device OM. Accordingly, the controlsection 27 a receives the resolution information from the digital cameraCA (step 202 (S202)). Receiving the resolution information from thedigital camera CA, the control section 27 a causes the display 4 to showthus received resolution information as depicted in FIG. 6 (step 203(S203)).

More specifically, in the state where no image data exist within themain memory 21, when the copy button 8 is pushed down, the informationin FIG. 5 is lighted for about one second in the LCD 4, and then theinformation in FIG. 6 is displayed there. Namely, in this state, whenthe copy button 8 of the operating section CP is pushed down (step 9(S9)), the control section 27 a of the external storage device OMtransmits a control signal corresponding to an operation for inspectingthe state of the main memory 21 to the communication buffer 22 by way ofthe transmitting and receiving circuits 26 and 23 (step 200 (S200)). Thecontrol section 15 of the digital camera CA detects the control signaltransferred to the communication buffer 22 and transmits, to the controlsection 27 a of the external storage device OM, information about thephotographing mode which has already been set within the ROM 16 inresponse to this control signal. Receiving this photographing mode(high-resolution mode) information (step 202 (S202)), the controlsection 27 a of the external storage device OM causes the LCD 4 to showthis information (step 203 (S203)).

The control section 27 a of the external storage device OM judgeswhether the copy button 8 is pushed down or not (step 204 (S204)). Whenit is judged that the copy button 8 is not pushed, the control section27 a judges whether 10 seconds have passed after step 203 (S203). Whenit is judged that 10 seconds have not passed after step 203 (S203), thecontrol section 27 a repeats the operation of step 204 (S204); whereas,when it is judged that 10 seconds have passed, the control section 27 arepeats the operation of step 2 (S2).

Namely, the LCD 4 shows this resolution information for a predeterminedperiod (10 seconds) as depicted in FIG. 6 (step 203 (S203)). During thisdisplay period, when the copy switch 8 is continuously pushed down, asnoted above, the control section 27 a of the external storage device OMtransmits, to the digital camera CA, a control signal for changing thesetting of the resolution within the ROM 16 of the digital camera CA(step 205 (S205)). The control section 15 of the digital camera CAreceiving this signal changes the photographing mode (function mode)within the ROM 16 from the high resolution to the low resolution,detects whether the photographing mode is changed or not, and, afterconfirming that the photographing mode has been changed, transmits thusconfirmed information to the control section 27 a of the externalstorage device OM. When the control section 27 a of the external storagedevice OM receives this information (step 206 (S206)), it causes the LCD4 to show the information about this change as depicted in FIG. 7 (step207 (S207)). This display is effected for three seconds with flickering.Thereafter, the LCD 4 shows the information in FIG. 4 again.

Thus, as the functional setting of the digital camera CA is performed bythe external storage device OM, the number of parts such as switches inthe main body of the digital camera CA can be reduced, thereby loweringthe manufacturing cost of the digital camera CA. Also, as suchfunctional setting of the digital camera CA is effected not by a largehost computer but by an external storage device having a size which canbe held with one hand, the convenience for its user can be remarkablyimproved.

As explained in the foregoing, when the functional setting of thedigital camera is effected by the external storage device separated fromthe digital camera, a quite convenient digital camera can be provided.Here, while modes of resolution are switched by the external storagedevice OM as the photographing mode in the foregoing embodiments;photographing modes such as flash lighting modes (strobe lighting modeand single lighting mode) and autofocus modes (spot autofocus,multi-autofocus, and macro-autofocus) of the digital camera may also beswitched by the external storage device OM.

From the invention thus described, it will be obvious that the inventionmay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

The basic Japanese Application No. 33852/1996 filed on Feb. 21, 1996 ishereby incorporated by reference.

What is claimed is:
 1. An external storage device connectable to adigital camera by a cable, said digital camera including a first memoryfor storing image data, a second memory for storing image data convertedfrom the image data in said first memory by a predetermined resolutionand a third memory including a program for controlling saidimage-data-conversion by said predetermined resolution, comprising: ahand-held size housing that can accommodate a recording medium; a singlecopy button provided on said housing; an LCD provided on said housing;and a control section, wherein, when said copy button is pushed once,said control section sends a first request to said digital camera forinformation about whether image data exists within said second memory,when said digital camera sends back the information indicating thatthere is image data within said second memory in response to said firstrequest to said control section, said control section sends a secondrequest to said digital camera requesting transmission of the image datawithin said second memory to said recording medium, when said digitalcamera sends back the information indicating that there is no image datawithin said second memory in response to said first request, saidcontrol section sends a third request to said digital camera requestinginformation about said predetermined resolution set in said thirdmemory, when said digital camera sends back the information regardingthe predetermined resolution set in said third memory to said controlsection, said LCD displays the information regarding the predeterminedresolution, when said copy button is pushed within the period that saidLCD displays the information regarding the predetermined resolution,said control section sends a fourth request to said digital camerarequesting the resolution set in said third memory be changed, therebycopy and resolution change actions are achieved by using said singlecopy button, and said external device is in a hand-held size.
 2. Anexternal device according to claim 1, in which all of the buttons onsaid housing consist of: said copy button; a power button operable tosupply power to said control section; and an erase button operable toerase said recording medium.
 3. A system comprising said external deviceand said digital camera as defined in claim 1.